** UNIVERSITY OF COLORADO AT BOULDER NEWS RELEASE **
Contact: Wayne Pryor, (303) 492-1259
Karen Simmons, 492-8363
Jim Scott, 492-3114
June 8, 1994
CU RESEARCHERS GEARING UP FOR COMET IMPACT ON JUPITER
Researchers from the University of Colorado at Boulder will use several
different observing facilities, including NASA's Galileo spacecraft, to
chart the expected fireworks when Comet Shoemaker-Levy plows into Jupiter
Wayne Pryor, a research associate at the Laboratory for Atmospheric and
Space Physics, said a CU-Boulder team will use an ultraviolet spectrometer
on Galileo to look for changes in Jupiter's atmosphere at the time of
impact. Some scientists are predicting about 20 comet fragments -- the
largest up to two miles across -- to slam into Jupiter between July 16 and
July 22, releasing the energy equivalent to the explosion of millions of
Galileo is slated to be about 122 million miles from Jupiter on July 16 --
the projected first day of impact -- and on the same side of the planet as
the collision, said Pryor. Launched in 1989 and slated to begin orbiting
the planet in December 1995, Galileo will be the nearest spacecraft to
Jupiter and the only one capable of zeroing in on small areas of the
Some astronomers are predicting the impact will generate a mushroom cloud
rising more than 1,000 miles above the Jovian atmosphere. Many suspect the
crash of a similar-sized object on Earth 65 million years ago wiped out the
dinosaurs and other land species. "We know that such comet impacts modify
planets and have affected Earth in the past," said Pryor. "This is our
chance to watch one in action."
The $2.4 million CU spectrometer on Galileo was designed to identify
"characteristic fingerprints" of gases found in planetary atmospheres by
detecting energy emissions from invisible bands of the light spectrum.
LASP researchers also modified a second extreme ultraviolet spectrometer
for the spacecraft.
The CU team plans to use the UV spectrometer to observe the "reflection
spectrum" of Jupiter and the surrounding sky prior to the event, the impact
of the particular comet fragment dubbed "P" on July 20 and the condensed
gas or ejected matter rising into the atmosphere, said Pryor. They also
hope to determine the approximate size of the fragment and the amount of
"We would like to know how much energy is released from the fireball and
how big of a splash is created by the event," he said. "Imagine what would
happen if a fragment one kilometer across hit Denver traveling at 60
kilometers a second."
Since comets are thought to contain primarily ice, the team expects to see
increases in atmospheric water as well as changes in ammonia, which is made
up of nitrogen and hydrogen. Other team members participating in the
experiment include LASP's Charles Hord, Charles Barth, Ian Stewart and
Because of Galileo's crippled high-gain antenna, the data will take weeks
or even months to trickle down to Earth for analysis, he said. Despite the
time lag created by the antenna problem, the CU instrument should provide
quality data, he said.
Pryor also is part of a national team that will make collision observations
with a 30-inch telescope at McDonald Observatory near Fort Davis, Texas.
The team will use high-tech imaging cameras equipped with special filters
to look for changes in Jupiter's high clouds as a result of the impact.
Another LASP researcher, Nicholas Schneider, will make observations from
the Las Campanas Observatory in Chile using a 100-inch telescope. Led by
John Trauger of NASA's Jet Propulsion Laboratory in Pasadena, the team will
look for changes in the charged-particle environment of Jupiter's
Schneider, who also is on a Hubble Space Telescope science team analyzing
the impact, said the observations may provide new clues to the chemical
ingredients of comets. But he and other CU-Boulder researchers cautioned
the impact could turn out to be far less spectacular than portrayed in the
In addition, John Bally of CU's astrophysical, planetary and atmospheric
sciences department will work with a team led by the University of Chicago
to make infrared observations of Jupiter with a 24-inch telescope from the
South Pole. Bally said the team hopes to observe the "excitation" of
molecular hydrogen molecules in the Jovian atmosphere as a result of
increased dust and to record the fireball created by the impact in the
infrared portion of the light spectrum.
LASP researcher Mihaly Horanyi has predicted the impact will result in the
formation of a new ring around the planet within 10 years. The ring, which
could be as bright or brighter than the current ring, will probably be
formed by dust from the break-up combined with dust produced along the
comet's trajectory path.
** UNIVERSITY OF COLORADO AT BOULDER NEWS RELEASE ** Contact: Charles Hord, (303) 492-7923, 492-6944 Jim Scott, 492-3114 Oct. 24, 1995 CU INSTRUMENTS ON GALILEO TURNED ON IN PREPARATION FOR JUPITER ENCOUNTER NASA officials at the Jet Propulsion Laboratory in Pasadena switched on two University of Colorado at Boulder instruments on board the speeding Galileo spacecraft last week in preparation for the long-awaited encounter with Jupiter. Senior researcher Charles Hord, principal investigator on the two ultraviolet spectrometers flying on Galileo, said they will be used to make periodic observations as it approaches Jupiter. Slated to begin orbiting Jupiter Dec. 7, the craft has traveled more than 2 billion miles on a roundabout journey to the giant planet since its October 1989 launch from the space shuttle Atlantis. "We think everything is in place, and now there is a sense of anticipation," said Hord, a senior researcher at CU's Laboratory for Atmospheric and Space Physics. "This has been a long mission, and we are anxious to see it bear fruit." The first target of the spectrometers, which can identify specific atmospheric gases, will be ultraviolet light emissions associated with Io, one of Jupiter's four large moons, said Hord. Scientists are interested in the composition and changing face of Io's torus, a donut-shaped ring of charged particles bound by Jupiter's magnetic field that was discovered during NASA's Voyager 1 flyby in 1977. Io has a number of active volcanoes spewing sulfur dioxide, which is broken into charged particles known as ions, said Hord. Sulfur and oxygen ions captured by the magnetic field of Jupiter produce ultraviolet light in the atmosphere that should be visible to UV and extreme UV spectrometers on board the spacecraft. "Just as Earth has an aurora, so does Jupiter," said Hord. "We are interested in how this aurora is formed. The volcanoes are putting out 'tracers' that can tell us more about Jupiter's magnetic field and how the planet system is evolving." The two spectrometers -- a UV instrument designed and built at CU-Boulder and an extreme UV spectrometer from the University of Arizona that was modified by CU researchers for the mission-- are among 10 instruments on the orbiter. Six others are on a probe released from the craft July 12, which will plummet through Jupiter's atmosphere Dec. 7 to study its chemical composition. The probe will send a steady stream of information back to the spacecraft during its 75-minute dive through the clouds before disappearing into the dense atmosphere. Once the spacecraft is orbiting Jupiter, the CU instruments will be used to take characteristic "fingerprints" of the gases in the jovian atmosphere, said Hord. The research team will look for evidence of ammonia and complex hydrocarbons like acetylene that are believed to be the building blocks of life. "When we look at Jupiter, it's like looking back on the history of Earth," said Hord. "Since Jupiter is so much more massive than Earth, it has retained all of its original gases. We think Earth had the same types of gases in its early history and we're interested in how life might have evolved in a primitive atmosphere." The spectrometers also will be used for close-up viewing of Europa, Callisto and Ganymede, Jupiter's three other large moons. The spacecraft will fly within 500 miles of the moons, more than 20 times closer than did the Voyager 1 spacecraft. "We want to see what types of gases may be coming off these moons," he said. Although their surfaces may be icy, "we will be looking for evidence of escaping water vapor to tell us how the moons are evolving," he said. "Who knows? We may well find something unexpected." Although mission scientists received a setback in 1991 when the primary antenna was found to be stuck in a closed position, engineers have since installed more sensitive radio receivers on Earth and are reprogramming the spacecraft with new software. "We think we will be able to do about 75 percent of the science we originally planned," said Hord. "But we have to make every picture and every observation count, and that puts a lot more pressure on us." Other LASP researchers on the Galileo spectrometer science team include Charles Barth, Larry Esposito, Bill McClintock, Wayne Pryor, Ian Stewart and Gary Thomas. The team also includes scientists from JPL and the University of Arizona. Data is being sent from the spacecraft to Deep Space Network antennas located in Goldstone, Calif., Madrid, Spain and Canberra, Australia. Information from the CU spectrometers is sent on to JPL, then forwarded over data lines to LASP's Space Technology Building in the CU Research Park. The incoming information will be analyzed by CU-Boulder faculty and students, Hord said. Martin Marietta Astronautics of Denver built three of the Galileo probe instruments and an electronic guidance system to control the spacecraft's balance.
You are visitor # 1
This page written by Pamme Crandall at LASP
Last Updated May 30, 1996
For Questions or Comments e-mail Karen Simmons